mutable keyword

Jack Applegame via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Mon May 23 01:19:52 PDT 2016


On Sunday, 22 May 2016 at 13:08:19 UTC, Jonathan M Davis wrote:
> Given how const and immutable work in D, having any portion of 
> them be treated as mutable, becomes highly problematic. It 
> could theoretically be done by having to mark such variables 
> with an attribute and mark such types with a similar attribute 
> so that the compiler knows that the type in question is not 
> really following the rules of const or immutable and thus 
> doesn't make any assumptions about it like it would normally, 
> but it risks getting rather complicated, and Walter is most 
> definitely not in favor of such an idea. He is absolutely 
> adamant that const is useless unless it's fully const with no 
> backdoors whatsoever. So, I'd be very surprised if any kind of 
> @mutable were added to the language. Certainly, you'd have to 
> have a very strong technical reason to convince him otherwise, 
> and odds are that he's just going to tell you to not use const, 
> if it's not going to work for the type to be const.
Ha-ha. All this does not prevent immutable class to have mutable 
monitor. Why D so often violates its own rules?



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